Short term investment - Need a guaranteed principal

[lambdb]

I'm looking at different options for return on some money that will be in holding for 6-8 months.

Amount will be between 500k and 2 mill.
The investment MUST be guaranteed principal.

Are U.S term deposits the way to go?
Segregated funds?
We got an offer from one bank of a direct investment return of 4.9% which seemed ok for a larger bank.

We have had trouble finding a guaranteed principal on some of the funds due to the short time frame.

Any Other Ideas or recommendations?

Lambdb